Flat panel displays are quickly becoming a dominant display technology. They range from liquid crystal (LCD) RGB displays, to plasma displays, to light emitting diode (LED) and organic light emitting diode (OLED) displays, projection displays using single or multiple LCD elements, and single or multiple micro-mirror elements.
A common problem shared by these technologies is yield. Perfect panels are very difficult to produce, and are very expensive. Pixel defects in LCD panels include stuck-on and stuck-off pixels. Typically, some number of defective pixels are allowed on a display panel. An ISO standard for pixel defects, ISO 13406-2, identifies three classes of standards for measuring pixel defects in flat panel displays. The most lenient class still only permits five full-brightness pixels, 15 full dark pixels, and 50 sub-pixel defects for a 15 or 17-inch panel. Most data displays strive to satisfy the Class 2 standard or better. This means that even for a process which has a very low defect rate per pixel, the probability of having a Class 3 panel of 1024×768 resolution is still quite low. With the resolution requirement of high definition television (HDTV, 1920×1080), pixel defect can severely limit yield and drive up the cost of good panels.
An approach to mitigate pixel defects could improve overall yields and influence price.